|Document Type:||Journal Article|
|Title:||Maternal control over offspring life history in a partially anadromous species (Oncorhynchus mykiss)|
|Author:||B. A. Berejikian, Lance A. Campbell, R. Bush|
|Journal:||Transactions of the American Fisheries Society|
|Keywords:||Oncorhynchus mykiss,life history,maternal effects,maturation,gonadosomatic index,partial anadromy|
Environmental variability among freshwater habitats may influence migratory decisions in partially anadromous salmonids through proximate effects on individual fish development and condition and through longer term genetic adaptations of populations to the various environments; however, the relative importance of the two factors has been difficult to sort out. We used gonadosmatic index as an indicator of maturation, and therefore residency, in age-1 and age-2 parr collected from eight partially anadromous Oncorhynchus mykiss populations occupying a diversity of freshwater habitats. Substantial environmental variability among eight Hood Canal streams had little effect on life history pathways in male and female offspring of anadromous females, with the exception of significantly higher maturation rates in male parr in one population (Little Quilcene). Between 0% and 8% of female parr produced by anadromous females had initiated maturation across all populations, compared with 33% (Duckabush River) or 53% (Hamma Hamma River) maturation in female offspring of resident females in the two populations with substantial resident populations. The results indicate strong maternal control over offspring life history pathways in systems where resident and anadromous forms are sympatric. Parr from resident mothers collected above and below anadromy barriers showed similar (females) or greater (males) odds of maturing. We concluded that, the expression of residency and anadromy in Hood Canal is more consistent with genetic adaptations to the diverse freshwater habitats, including strong effects of O. mykiss sequestered above anadromy barriers, than phenotypically plastic responses of parr to the environmental variability among streams.
The manuscript describes maternal and environmental control over maturation decisions in Oncorhynchus mykiss
|Theme:||Recovery, Rebuilding and Sustainability of Marine and Anadromous Species|
Characterize vital rates and other demographic parameters for key species, and develop and improve methods for predicting risk and viability/sustainability from population dynamics and demographic information.
Develop methods to use physiological and biological information to predict population-level processes.